✨ add pixel data hashing

backend/routes/templates.go

@@ -5,11 +5,13 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"math/rand"
 	"net/http"
 	"os"
 	"os/exec"
 
+  "github.com/NethermindEth/juno/core/crypto"
+  "github.com/NethermindEth/juno/core/felt"
+
 	"art-peace-backend/backend"
 )
 
@@ -21,10 +23,14 @@ func InitTemplateRoutes() {
 
 // TODO: Add specific location for template images
 
-func hashTemplateImage(imageData []byte) string {
-  // TODO: Use poseidon hash to hash image data and return hash
-  //       Make sure the hash matches the hash generated by the contract
-  return "hash" + string(rand.Intn(1000000))
+func hashTemplateImage(pixelData []byte) string {
+  var data[]*felt.Felt
+  for _, pixel := range pixelData {
+    f := new(felt.Felt).SetUint64(uint64(pixel))
+    data = append(data, f)
+  }
+  hash := crypto.PoseidonArray(data...)
+  return hash.String()
 }
 
 func imageToPixelData(imageData []byte) []byte {